单项选择题

4层螺旋CT的分辨力是

A.横向分辨力为0.5mm,纵向分辨力为0.5mm
B.横向分辨力为0.5mm,纵向分辨力为1mm
C.横向分辨力为1mm,纵向分辨力为0.5mm
D.横向分辨力为1mm,纵向分辨力为1mm
E.横向分辨力为1mm,纵向分辨力为2mm